This study was conducted to investigate the effects of different levels of coriander (Coriandrum sativum) seed powder and extract on the performance and carcass characteristics of broiler chickens. A total of 420 day-old broiler chicks (Ross 308) were allocated randomly into seven treatments of 60 birds per group. Each treatment had four replicates (15 chicks per replicate). The trial was designed with seven treatments, consisting of a control diet without coriander, this is, the control group (CG); three treatments, which included the control diet plus three levels of coriander extract in water (750, 1000, and 1250 mg/kg); and the another three, which received the control diet plus three levels of coriander powder (1.5%, 2.0% and 2.5%). Performance parameters were monitored throughout the experimental period. At 21 - 42 d old, the inclusion of 952 mg/kg of coriander extract in drinking water maximized weight gain, while the feed intake of the experimental period (1 - 42 d) was maximized at the coriander powder level of 1.2%. Feed conversion ratios improved with the inclusion of coriander powder in the diet throughout the experimental period. These results suggest that coriander powder in the diet and coriander extract in water could replace synthetic antibiotics and could be regarded as natural feed additives and growth promoters in poultry diets.